Quark model, partial symmetry and a unified scheme for PBBL and VBBL couplings

Abstract

The general ideas of the quark model used previously for the construction of couplings of baryons (B) and their resonances (BL) to pseudoscalar (P) mesons are extended to include their couplings also to vector mesons (V) through Schwinger's partial-symmetry method which provides a simple means of relating the VBB L to the PBB L vertices. The latter in turn are provided by a semi-relativistic model of broken SU6×O3 recently proposed by the author through an explicit ansatz for the form factors on the relevant masses, which enables a single parameter to describe an entire supermultiplet transition. The model is applied to the NΠΠ modes of several N- and Δ-type resonances, via the Nρ mechanism. The results suggest that, analogously to the ω→3Π case, an Nρ intermediate state, even when energetically forbidden, could still provide an important alternative to the Δπ mechanism for Nππ modes.